Although many people consider GMC and Chevrolet's trucks to be interchangeable, GMC has been working hard to establish its own identity, something the company likes to call "professional grade." The 2012 GMC Sierra Heavy Duty (HD) trucks are a good example of this new image, sharing almost all of their parts with the Chevrolet Silverado HD trucks, but adding more upscale features such as the Denali trim line, which has no equal on the Chevy side. The 2012 Sierra HD trucks are a powerful lineup of 3/4-ton and 1-ton models, made all the better by last year's improvements to the frame, suspension and Duramax diesel engine. And, while the 2012 GMC Sierra HD trucks are not the most powerful in the segment, they do take top honors for fifth-wheel and conventional towing, as well as payload.

You'll Like This Car If...

If you're a GMC loyalist, the 2012 GMC Sierra HD truck line is bound to keep you coming back for more. Those who worry about dirtying up the inside of their truck will appreciate the heavily vinyl trappings of the Work Truck line.

You May Not Like This Car If...

Although both the Ram HD and Ford Super Duty trucks look nearly identical on paper, the two competitors offer bolder styling and more upscale editions than does the 2012 GMC Sierra HD line.

What's New for 2012

The 2012 GMC Sierra HD sees a few improvements for this model year. A new hard-drive navigation radio is offered, while Work Truck models gain cruise control and lockable spare tire. Denali trims gain as standard equipment heated and cooling front seats, a heated steering wheel, a rearview camera and, on 3500 dually models, 17-inch polished wheels.

GMC HD's available Duramax turbodiesel develops 397 horsepower and 765 pound-feet of torque (that's more horsepower but less torque than the Ram HD, and less horsepower and torque than the Ford PowerStroke diesel). Despite the difference in power from its main rivals, the Sierra HD still takes top honors in fifth-wheel and conventional towing, as well as payload figures. The Duramax diesel is a bit loud, but you wouldn't know it from inside the passenger compartment. One of our favorite features on the diesel truck is the "smart" exhaust-braking setup. The system works by progressively restricting the diesel's exhaust, depending on speed and grade, to help slow the rig with added compression braking. We tested a number of 2012 GMC Sierra HD trucks, with gasoline and diesel engines, long and short beds, and basic to plush trim levels. We found all exhibited a firm suspension, good steering ability and fairly compliant ride.

Favorite Features

Exhaust braking This system progressively restricts the diesel's exhaust – depending on speed and grade – to help slow the rig with added compression braking.

Remote startingA favorite on any vehicle, this available feature is much appreciated on working trucks that operate in hot and cold weather extremes.

2012 GMC Sierra 2500 HD Crew Cab Details

Interior

The 2012 GMC Sierra HD Work Truck (WT), SLE and SLT interiors are designed to work in conjunction with the trucks' duties, yet are still nicely appointed and on Denali trims, downright opulent. While there are not as many storage bins and compartments as in the Ram and Ford HD trucks, the 2012 GMC Sierra HD nevertheless has a number of useful storage ideas for everything from laptops to the errant tool. The 2012 GMC Sierra HD truck's cab makes for the perfect mobile office, with such options as mobile Wi-Fi, Bluetooth and navigation, as well as SiriusXM NavTraffic updates and the OnStar suite of telematic aids. Denali models feature specific brushed-aluminum trim, heated and cooling 12-way power seats, power-adjustable pedals, and a Bose premium surround audio system.

Exterior

The 2012 GMC Sierra 2500 and 3500 HD trucks sport a large, 3-bar chrome grille resting atop a full-size chrome bumper to create as imposing a sight as you'll ever want see in your rearview mirror. The Sierra HD's massive power dome hood is decked out in powertrain badging and features functional louvers for better engine cooling. The upscale Denali trims can be spotted by their 4-bar mesh design grille and color-keyed bumpers fitted with a mesh-style lower air intake surrounding the front tow hooks. Other features unique to the Denali include chrome door handles and accents, and polished forged-aluminum wheels.

Notable Equipment

Standard Equipment

Four-wheel-disc brakes with ABS and Intelligent Brake Assist and a 6-speed automatic transmission are standard on all models, while StabiliTrak electronic stability control, Trailer Sway Control and Hill Start Assist (but not Hill Descent Control) are standard on single-rear-wheel (non-dually) models, and a "Smart" Exhaust Braking comes with the available Duramax Diesel. Also standard are chrome front and rear bumpers, engine- and transmission-oil coolers, a driver information center, tilt steering wheel, cruise control, air conditioning, automatic headlights and front tow hooks. Standard safety features include front-seat airbags and a new high-strength tubular steel-frame crossmember that improves crashworthiness.

Optional Equipment

Optional (or unavailable) on base 2WD GMC Sierra Work Trucks are power locks, windows and mirrors and a rear-window defroster. The next-level SLE trim provides those plus remote keyless entry, OnStar, XM Satellite Radio, and a CD player, but not the rear-window defroster. The top-of-the-line SLT trim (available on Extended and Crew Cab models) adds leather, power seats and much more, while Denali models are fully loaded. Option packages are available, and other major options include navigation, a CD changer, a rear-seat DVD entertainment system, remote start, premium wheels, a sunroof, a rearview camera, an integrated trailer-brake controller and pelvic/thorax and head-curtain airbags.

Under the Hood

The 2012 GMC Sierra HD features as standard a heavy-duty Vortec 6.0-liter gasoline V8 with a cast-iron block, aluminum heads and cam-in-block variable valve timing (VVT). The VVT system allows the engine to use late intake valve closing to improve efficiency and achieve an optimal balance of low-rpm torque and free-breathing, high-rpm horsepower. The 2012 Duramax turbodiesel offers plentiful power and torque, improved strength and durability, and a "smart" exhaust braking with the Allison 1000 6-speed automatic transmission and full B20 biodiesel capability. Its NOx emissions are reduced by 63 percent via a Selective Catalyst Reduction after-treatment system that uses urea-based Diesel (Emission) Exhaust Fluid (DEF) in a 5.3-gallon tank that needs to be replenished about every 5,000 miles.

"Bought new in 2004, 2007 and 2013. Love this truck. Fuel rail went out in 2004 model at 80K but dealer R&R'd at no charge and paid for rental truck and hotel. Traded 2004 for new 2007. The 2007 developed cooling problems at 150K. Traded 2007 for new 2013. The 2013 has 60K to date with no problems. I would buy another in a heartbeat but the prices have shot through the roof."

"This Sierra rides better than my cars. It's been great for hauling things back & forth to NY, I am working there on a temporary basis. It fits my lifestyle well for canoeing, Kayaking, biking, hauling my zero turn lawnmower and the occasional home project. It's been great in the snow in upstate NY. Never had any issues starting it. Completely dependable. I'd never be without a full size truck again. I owned an S10 prior and had 240,000 miles in the inline 4 when I bought the Sierra. I figured if that GM 4 banger could last that long I'd get a full size and it should do better. I did consider the Toyota Tacoma and am glad I bought the Sierra, that bed size has been very handy. I'll never go back to a small truck again. My next truck is going to be a Sierra."

"The one thing I would change on it is the engine. The V8 available for this year got about 6 mpg better mileage on average. Otherwise the V6 has been more than adequate for all my needs. I do a lot of highway travel as well as in town, and am happy with comfort, performance and ride. I do not plan to replace this truck any time soon \, at least before it reaches 300,000 miles. Would I buy it again. You bet, in a heartbeat."

Best truck I have EVER owned.........love it!!

Reviewer Ratings

Overall Rating

10/10

Value

9/10

Reliability

9/10

Quality

10/10

Performance

9/10

Styling

10/10

Comfort

9/10

Pros: "Just a GREAT truck"

Cons: "None"

Likely to recommend this car? (1-10): 10

"Smooth riding, plenty of power, turns on a dime ( unlike last truck) I pull a fairly heavy boat/ trailer, can't hardly tell it's behind me. Gas mileage is decent in the city and excellent on the highway. And with the flex fuel option, whenever gas gets expensive, I switch to good old "corn oil"......big savings!
Best part........truck is gorgeous! Always get comments about what a " good looking truck I have" :)"